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#   Copyright (c) Jeremy Lainé.
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import datetime

NTP_EPOCH = datetime.datetime(1900, 1, 1, tzinfo=datetime.timezone.utc)


def current_datetime() -> datetime.datetime:
    return datetime.datetime.now(datetime.timezone.utc)


def current_ms() -> int:
    delta = current_datetime() - NTP_EPOCH
    return int(delta.total_seconds() * 1000)


def current_ntp_time() -> int:
    return datetime_to_ntp(current_datetime())


def datetime_from_ntp(ntp: int) -> datetime.datetime:
    seconds = ntp >> 32
    microseconds = ((ntp & 0xFFFFFFFF) * 1000000) / (1 << 32)
    return NTP_EPOCH + datetime.timedelta(seconds=seconds, microseconds=microseconds)


def datetime_to_ntp(dt: datetime.datetime) -> int:
    delta = dt - NTP_EPOCH
    high = int(delta.total_seconds())
    low = round((delta.microseconds * (1 << 32)) // 1000000)
    return (high << 32) | low
